Recently, the discovery of the new family of crystalline mesoporous materials M41S by researchers at Mobil Corp. (U.S. Pat. No. 5,108,725) has attracted great attention. These mesoporous molecular sieves with adjustable and uniformed pore sizes in the range of 1.5 to 10.0 nm can be applied in various fields. MCM-41, one member of this series, possessing a hexagonal arrangement of uniformly sized channel mesopores, has been the focus of the most recent applications in catalysts and absorbents for larger molecules.
Since the MCM-41 materials were synthesized from a complex mixture of surfactants and silicate, the behavior and the structure of the system might be variable. However, the previous literature reported that the morphology of MCM-41 material was limited in microparticles. This is caused by two reasons. One is that the MCM-41 structure was always prepared from acidifying highly condensed silicate form; it is too rigid to bend into other large-scaled morphologies. Second, there is no suitable micron-sized template existed in the synthetic composition to prepare the hierarchical structure. Therefore, there is an opportunity to tailor the morphology of MCM-41 products to a designed structure by using a soft or less condensed silicon source and a proper composition promoting the formation of micron-sized template.
Based on the theory of surfactant complex fluids, the morphology of aggregates formed by self-assembly of surfactants in solution and the evolution of morphology with additives, such as alcohol with medium chain length, is of current interest. Thus, we added a proper amount of alcohol into surfactant-silicate synthetic system to produce the mesoporous materials with special micron-sized morphologies.